JP2018179885A - Ground fault detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ground fault detection device capable of identifying a faulty power line as much as possible in the event of a ground fault.SOLUTION: A ground fault detection device comprises: a ground fault current detector 46 configured to detect ground fault current that flows through a faulty power line and housing when a ground fault occurs, and to generate an output corresponding to the magnitude of the ground fault current; and a power line identifier 41 configured to identify a power line with the ground fault based on at least either of the magnitude and a variation pattern of the ground fault current represented by the output of the ground fault current detector 46.SELECTED DRAWING: Figure 2

Description

  BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a device for detecting a ground fault of a current-carrying wire respectively connected to a plurality of electronic components included in various devices such as a water heater.

  In various devices, a plurality of conducting wires (so-called conducting wires forming a harness) for energizing power for operation of a plurality of electronic components are disposed in the interior of a housing. In this type of device, the coated tube (insulation tube) of any of the current-carrying wires is damaged due to vibration, impact, etc. acting during manufacture, installation, maintenance, etc., or from the outside. Also, a phenomenon in which the conducting wire is electrically conducted to the conductor portion of the casing, a so-called ground fault may occur.

  If such a ground fault occurs, an abnormal current may flow in the device, or there is a possibility that the malfunction of the device, an erroneous detection, or the like may occur, a device for detecting the occurrence of the ground fault has been proposed conventionally. (See, for example, Patent Documents 1 to 3 and the like).

Unexamined-Japanese-Patent No. 5-336649 Unexamined-Japanese-Patent No. 11-271378 JP, 2013-199874, A

  In equipment equipped with a large number of electronic components, there are also a large number of current-carrying wires that can cause ground faults. Therefore, when a ground fault occurs, not only is the occurrence of the ground fault detected, but the ground fault is not It is desirable to be able to identify as much as possible whether it has occurred.

  However, in the prior art disclosed in Patent Document 1 etc., it is not possible to identify the current-carrying wire in which the ground fault has occurred from a large number of current-carrying wires.

  For this reason, conventionally, in a device provided with a large number of current-carrying wires that may cause a ground fault, when a ground-fault occurs, a contractor or the like has an operation of specifying the current-carrying wire having a ground fault from a large number of current-carrying wires. It will be necessary. And there is a disadvantage that the work is likely to require a large number of man-hours.

  The present invention has been made in view of the above background, and it is an object of the present invention to provide a ground fault detection device which makes it possible to specify as much as possible the current-carrying line in which the ground fault has occurred when a ground fault occurs. I assume.

A ground fault detection device according to the present invention is an apparatus provided with a housing in which conductive wires for energizing a plurality of electronic components are disposed in order to achieve the above object, any of the conductive portions of the housing and When a ground fault occurs, which is a phenomenon of conduction between the current carrying wire of the electronic component and any of the electronic components, it is specified which electronic component for which the current carrying wire has a ground fault. A ground fault detection device having a function to
When the ground fault occurs, a ground fault current which is a current flowing through the conductive line and the casing in which the ground fault has occurred is detected, and an output corresponding to the magnitude of the ground fault current is generated. Ground current detector,
The current-carrying wire in which the ground fault has occurred is identified based on at least one of the magnitude of the ground fault current indicated by the output of the ground fault current detector and the change pattern of the magnitude of the ground fault current. And a wire specifying unit (first invention).

  Here, in an apparatus including a plurality of electronic components, the magnitude of the power supply voltage of each electronic component, or the change pattern of the conduction current of each electronic component, or the impedance of the conduction circuit of each electronic component, etc. There are many cases depending on the type of

  For this reason, when a ground fault occurs in the current-carrying wire (current-carrying wire for energizing the electronic component) corresponding to a certain electronic component, the magnitude of the ground current indicated by the output of the ground current detector, or The change pattern is often characteristic to which electronic component the current conducting wire in which the ground fault has occurred corresponds to the current carrying wire.

  Therefore, the current-carrying wire identification unit is configured to cause the ground fault based on at least one of the magnitude of the ground fault current indicated by the output of the ground fault current detector and the change pattern of the magnitude of the ground fault current. Identify the conducting wire where the

  Thus, according to the first aspect of the invention, it is possible to specify as much as possible the current-carrying wire in which the ground fault has occurred.

  In the first aspect of the invention, the current-carrying-wire identification unit is configured such that the magnitude of the ground fault current indicated by the output of the ground fault current detector when the ground fault occurs is of a plurality of types set in advance. And the judgment result as to which kind of change pattern among the plurality of kinds of change patterns set in advance. According to at least one of the determination results, the current-carrying wire in which the ground fault has occurred may be identified (a second invention).

  According to this, it is possible to classify and identify the current-carrying wire in which the ground fault has occurred into as many types as possible.

  In the first invention or the second invention, the conductive wire identification unit uses the fluctuation frequency of the magnitude of the ground fault current indicated by the output of the ground fault current detector as an index representing the change pattern. The present invention can be configured to identify a current-carrying wire in which a ground fault has occurred (the third invention).

  That is, among the plurality of electronic components, in many cases, a plurality of electronic components having different frequencies of energization are included. In this case, by using the fluctuation frequency of the magnitude of the ground fault current indicated by the output of the ground fault current detector as an index representing the change pattern, the current carrying wire in which the ground fault has occurred is subjected to the fluctuation of the ground fault current It becomes possible to classify and identify based on frequency.

  In the first to third inventions, regarding at least a part of the plurality of conductive lines among the conductive lines for each of the plurality of electronic components, which one of the plurality of conductive lines of the part is In the case of specifying whether a ground fault has occurred, it is determined whether or not a ground fault has occurred in the current carrying line, for each of the plurality of current carrying lines. The present invention can be configured to execute in a predetermined order with respect to (4th invention).

  In the fourth aspect of the invention, the step of executing the determination process on the part of the plurality of current carrying lines in a predetermined order is a process in which the first predetermined one of the plurality of current carrying lines is selected. The first determination process is performed on the current-carrying wire, the second determination process is performed on the predetermined second current-carrying wire, and the third determination process is performed on the predetermined third current-carrying wire. This means that the determination process is performed in order in such a manner that the determination process is performed.

  According to the fourth aspect of the invention, the process of determining whether or not a ground fault has occurred for each of the plurality of conductive lines is executed in an order suitable for enhancing the reliability of the determination process. It is possible to As a result, the reliability of the identification result of the current-carrying wire in which the ground fault has occurred can be enhanced.

  In the first to fourth inventions, in order to determine whether or not a ground fault has occurred in a predetermined current-carrying wire among the current-carrying wires of the plurality of electronic components, the current-carrying-wire identification unit Operating the electronic component corresponding to the predetermined current-carrying wire, the magnitude of the ground fault current indicated by the output of the ground fault current detector in the operating state, and the change pattern of the magnitude of the ground fault current According to at least one of them, it may be configured to determine whether or not a ground fault of the predetermined current-carrying wire has occurred (the fifth invention).

  Here, with regard to an electronic component, when a ground fault of the current-carrying wire corresponding to the electronic component occurs in the operating state of the electronic component, the magnitude of the ground fault current indicated by the output of the ground fault current detector And at least one of the patterns of change in magnitude of the ground current may be characteristic.

  Therefore, according to the fifth aspect of the invention, when a ground fault of the current-carrying wire corresponding to such an electronic component occurs, it is possible to appropriately identify the current-carrying wire.

  In the first to fifth inventions, the conductive wire identification unit may set the ground in each of different modes in a standby state in which the operation of the device is not performed and an operation state in which the operation of the device is performed. The present invention can be configured to identify a current-carrying wire in which a fault has occurred (sixth invention).

  That is, when a ground fault occurs in a current-carrying wire corresponding to any electronic component, the magnitude of the ground fault current indicated by the output of the ground fault current detector or the change pattern thereof is the standby state of the device. In many cases, it differs from the driving condition. Therefore, according to the sixth aspect of the present invention, it is possible to improve the reliability of the identification result of the current-carrying wire in which the ground fault has occurred.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows roughly the principal part structure of the water heater as an apparatus of one Embodiment of this invention. The figure which shows the connection structure of the electronic circuit unit and electronic component with which the water heater of embodiment was equipped. The figure which shows the connection structure of the electronic circuit unit and electronic component with which the water heater of embodiment was equipped. FIG. 3 is a diagram showing a circuit configuration of a ground fault detection circuit shown in FIG. 2; The figure for demonstrating the operation | movement of the ground fault detection circuit at the time of generation | occurrence | production of a ground fault. The figure which illustrates the range of the magnitude | size of the voltage which the ground fault detection circuit outputs in the standby state of the water heater of embodiment. The figure which illustrates the range of the magnitude | size of the voltage which the ground fault detection circuit outputs at the time of the action | operation of the electronic component of embodiment. The flowchart which shows the processing of the microcomputer with which the water heater of an embodiment was equipped. The flowchart which shows the processing of the microcomputer with which the water heater of an embodiment was equipped. The flowchart which shows the processing of the microcomputer with which the water heater of an embodiment was equipped. The flowchart which shows the processing of the microcomputer with which the water heater of an embodiment was equipped.

  One embodiment of the present invention will be described below with reference to FIGS. Referring to FIG. 1, in the present embodiment, the device 1 to be subjected to ground fault detection is, for example, a bath water heater with a hot water heating function. FIG. 1 schematically shows a main part configuration of the apparatus 1 (hereinafter simply referred to as a water heater 1).

  The water heater 1 has a housing 2 installed outdoors. The housing 2 is a casing on which the main components of the water heater 1 are mounted, and the whole or a part thereof is made of a conductor such as metal. And the whole or the conductor part of this housing | casing 2 is earth | grounded to the earth side via the cable 2g for earthing | grounding.

  Inside the housing 2 are housed a plurality of burners (burner for hot water supply, burners for bath / heating) and a plurality of heat exchangers (heat exchanger for hot water supply, heat exchanger for bath / heating) not shown. It is done. Then, a fuel pipe 3 for supplying a fuel gas to a burner, a water supply pipe 4 for introducing hot water for heating (tap water etc.) into the casing 2, a heated water for hot water supply (hot water) for kitchen, bathroom etc. A hot water supply pipe 5 for supplying water, bath tub pipes 6a and 6b for flowing bath water (hot water), and hot water pipes 7a and 7b for flowing hot water for heating are extended from the inside of the housing 2.

  Furthermore, an electronic circuit unit 10 functioning as a control device responsible for operation control of the water heater 1 is housed inside the housing 2. The electronic circuit unit 10 has a substrate 11 fixed to the housing 2 via a bracket or the like (not shown). Wiring patterns (not shown) are formed on the substrate 11, and various circuit elements described later are mounted.

  Furthermore, a plurality of harnesses 12, 12, ... are connected to the substrate 11 through the connectors 13, respectively, and the power cord 14 and the ground wire for receiving the power of the commercial power supply as the power supply of the water heater 1 15 are connected via the connector 16.

  The power supply cord 14 is connected to the outlet of a commercial power supply through a not-shown earth leakage breaker. Further, the ground line 15 is grounded to the conductor portion of the housing 2, and is further grounded to the ground side via the housing 2.

  Each harness 12 is a bundle of a plurality of conducting wires, and electrically connects a plurality of electronic components to be described later and the substrate 11, respectively. In this case, each harness 12 for connecting the electronic component disposed in the housing 2 and the substrate 11 is disposed in the housing 2. In addition, each harness 12 (for example, a harness 12 d described later) for connecting the electronic component disposed outside the housing 2 and the substrate 11 is from the connector 13 on the substrate 11 side to a predetermined lead-out portion of the housing 2 It is disposed inside, and is further led out of the casing 2 from the lead-out portion.

  In the present embodiment, representative circuit elements mounted on the substrate 11 and representative electronic components connected to the substrate 11 via the harness 12 will be described below with reference to FIGS. 2 and 3. .

  As shown in FIGS. 2 and 3, the water heater 1 of the present embodiment drives, for example, a motorized valve (not shown) (such as a three-way valve in a water flow passage) as an electronic component connected to the substrate 11 via the harness 12. ... and the temperature fuse 22 which is disconnected when a predetermined portion in the housing 2 is overheated, and all the burners (hot water supply burners, baths and heating burners) in the housing 2 ) And a plurality of gas solenoid valves 24 and 24 for opening and closing the fuel supply path for each burner downstream of the gas main valve 23. The plurality of (two in the illustrated example) thermistors 25, 25 for detecting the hot water supply temperature etc., the water amount sensor 26 for detecting the water supply flow rate in the water supply pipe 4, and the tub Amount of hot water that is the flow rate of hot water Hot water level sensor 27 to be detected, floor heating remote control 28 for the operation of the floor heating system, bathroom heating remote control 29 for the operation of the bathroom heating system, and a hot water beam for opening and closing the hot water flow path of the bathtub It includes a valve 30 and a refill valve 31 for opening and closing a water passage for refilling water in the heating hot water flow path.

  In the present embodiment, the stepping motors 21, 21, ... are connected to the substrate 11 through the harness 12a and the connector 13a, and the temperature fuse 22, the gas source valve 23, the gas solenoid valves 24, 24, ... are harnesses. It is connected to the board | substrate 11 via 12b and the connector 13b.

  The thermistors 25 and 25, the water amount sensor 26, and the hot water amount sensor 27 are connected to the substrate 11 through the harness 12c and the connector 13c, and the floor heating remote control 28 and the bathroom heating remote control 29 are the harness 12d and the connector 13d. The hot water valve 30 and the refill valve 31 are connected to the substrate 11 via the harness 12e and the connector 13e.

  Here, each of the harnesses 12 a to 12 e is a harness disposed with at least a portion thereof in contact with or in proximity to the conductor portion of the housing 2. Therefore, in each of the harnesses 12a to 12e, any conductive wire included in the harness is electrically conducted to the conductor portion of the housing 2 due to biting or damage of the covering tube (not shown). It is possible to be in a state, that is, in a ground fault state.

  In addition, in this embodiment, as an electronic component contained in the water heater 1, the electronic component shown in FIG.2 and FIG.3 was illustrated typically. However, the electronic components included in the water heater 1 may include electronic components other than those shown in FIGS. 2 and 3. For example, the electronic component may include another substrate other than the substrate 11. Alternatively, the electronic component of any of the electronic components shown in FIGS. 2 and 3 may not be provided. Further, the combination of the type of electronic component and the harness, or the layout of the connector on the substrate 11 is not limited to the aspect shown in FIGS. 2 and 3.

  Further, the water heater 1 of the present embodiment is, as a circuit element mounted on the substrate 11, for example, as shown in FIG. 2, a microcomputer (micro computer) 41 that executes control processing related to operation control of the water heater 1; A power supply circuit 42 for generating a DC power supply voltage of a predetermined voltage for operating each of the electronic components and the circuit elements such as the microcomputer from the power (AC power) of a commercial power supply, and the stepping motor 21 according to a control command of the microcomputer 41 , 21 and so on, and the motor control of the gas source valve 23 and each gas solenoid valve 24 according to the control command of the microcomputer 41 and the motor drive circuits 43, 43,. A solenoid valve drive circuit 44 for performing opening / closing control of the gas main valve 23 and each gas solenoid valve 24), the gas main valve 23 and each gas when the temperature fuse 22 is disconnected, etc. Grounding of the current-carrying wire of any of the harnesses 12 forcibly closing the energization of the magnetic valve 24 (thus forcibly closing the main gas valve 23 and the gas solenoid valves 24) and the forced closing circuit 45 When a ground occurs, a ground fault detection circuit 46 detects the temperature, a detection signal of the temperature by each of the thermistors 25, a detection signal of the water flow rate by the water quantity sensor 26, and A detection circuit 47 receiving detection signals and inputting detection information thereof to the microcomputer 41, a communication circuit 48 relaying communication between the floor heating remote control 28 and the bathroom heating remote control 29, and the microcomputer 41, the microcomputer 41 According to the control command of the microcomputer 41 and the hot water valve drive circuit 49 that performs the energization control of the hot water valve 30 (thus, the opening and closing control of the hot water valve 30) according to the control command of Energization control the water valve 31 (and therefore, the opening and closing control of Homizuben 31) and a refill valve drive circuit 50 for.

  The input side (primary side) of the power supply circuit 42 is connected to the power supply cord 14 via the connector 16, and the power (AC power) of the commercial power supply is input from the power supply cord 14. The power supply circuit 42 includes a power conversion circuit (power conversion circuit of a switching system) of a known configuration including a transformer (not shown), and generates and outputs a DC power supply voltage of a predetermined voltage by the power conversion circuit. Is configured as. .

  Here, the DC power supply voltage generated by the power supply circuit 42 is three types of DC voltages of 5 V, 12 V, and 24 V in the present embodiment. 5 V is the operation voltage of the microcomputer 41 and each thermistor 25 etc. 12 V is each stepping motor 21, thermal fuse 22, gas source valve 23, gas solenoid valve 24, water quantity sensor 26, hot water quantity sensor 27, hot water quantity The operating voltage of the valve 30 and the refill valve 31 etc., 24 V is the operating voltage of the floor heating remote control 28 and the bathroom heating remote control 29.

  The wiring pattern of the substrate 11 serves as a reference potential portion of the power input from the commercial power source to the power supply circuit 42, the chassis ground potential portion 61 grounded to the casing 2 via the ground line 15, and the power supply circuit The secondary side ground 62 as a reference potential portion (a reference potential portion on the output side (secondary side) of the power supply circuit 42) of the DC power supply voltage generated by 42 and 5V and 12V with respect to the secondary side ground 62 , And 24 V DC power supply voltage is applied to 5 V potential portion 63, 12 V potential portion 64, and 24 V potential portion 65, respectively.

  In this case, in the power supply circuit 42, the housing ground potential unit 61 and the secondary side ground 62 are electrically isolated from each other via a transformer. The output side (secondary side) of the power supply circuit 42 is connected to the secondary side ground 62, the 5 V potential portion 63, the 12 V potential portion 64, and the 24 V potential portion 65 on the substrate 11, and the 5 V potential portion The DC power supply voltages of 5 V, 12 V and 24 V are respectively output between the secondary side ground 62 and each of the 63 V, 12 V potential parts 64 and 24 V potential parts 65.

  More specifically, the DC power supply voltage of 5 V generated by the power supply circuit 42 is a voltage that matches 5 V or substantially matches 5 V within a predetermined range. The same is true for the 12 V DC power supply voltage and the 24 V DC power supply voltage.

  Each motor drive circuit 43 is connected on the substrate 11 to the 12 V potential portion 64 and the secondary side ground 62 so that a DC power supply voltage of 12 V is applied. Furthermore, each motor drive circuit 43 is connected to the corresponding stepping motor 21 via the current-carrying wire of the harness 12a so as to supply power to the corresponding stepping motor 21 and also receives a control command from the microcomputer 41. The microcomputer 41 is connected on the substrate 11.

  Then, each motor drive circuit 43 supplies the electric power generated from the DC power supply voltage of 12 V to the stepping motor 21 in accordance with the control command given from the microcomputer 41, whereby the required operation of the stepping motor 21 (control command Is configured to perform an operation corresponding to

  Power supply (application of voltage) from each motor drive circuit 43 to the corresponding stepping motor 21 is intermittently performed at a predetermined drive frequency (for example, 125 Hz).

  The thermal fuse 22 is a harness for the 12 V potential portion 64 and the forced valve closing circuit 45 so that a DC power supply voltage of 12 V can be supplied from the 12 V potential portion 64 to the forced valve closing circuit 45 via the thermal fuse 22. It is connected via a conducting wire 12b. Therefore, the forced valve closing circuit 45 is connected to the 12 V potential portion 64 via the temperature fuse 22 and the conduction line of the harness 12 b (the conduction line connected to both ends of the temperature fuse 22).

  Then, the forced valve closing circuit 45 outputs the DC power supply voltage of 12 V supplied from the 12 V electric potential unit 64 via the temperature fuse 22 to the gas source valve 23 and the respective solenoids (not shown) of the gas solenoid valves 24. As is obtained, the solenoids of the gas source valve 23 and the gas solenoid valves 24 are connected to the solenoids of the gas source valve 23 and the gas solenoid valves 24 via the electric wires of the harness 12b.

  Therefore, when the thermal fuse 22 is broken, the DC power supply voltage of 12 V is not supplied to the forced valve closing circuit 45. Therefore, the output of the DC voltage of 12 V from the forced valve closing circuit 45 to the respective solenoids of the gas main valve 23 and the gas solenoid valves 24 is also shut off.

  Of the conduction lines of the harness 12b, the conduction line 12b1 of the 12V power source is branched from the conduction line between the temperature fuse 22 and the forced valve closing circuit 45. The conducting wire 12b1 is used as a conducting wire for supplying a DC power supply voltage of 12 V to the water quantity sensor 26, the hot water quantity sensor 27, the hot water filling valve 30, and the water filling valve 31, as shown in FIG.

  Further, the forced valve closing circuit 45 further includes the solenoid valve driving circuit 44 and the microcomputer 41 to receive a signal output from the solenoid valve driving circuit 44 when the operation of the solenoid valve driving circuit 44 is abnormal or a control command from the microcomputer 41. And on the substrate 11. Then, the forced valve closing circuit 45 receives 12 V to the respective solenoids of the gas source valve 23 and each gas solenoid valve 24 according to the above signal given from the solenoid valve drive circuit 44 or the control command given from the microcomputer 41. It is comprised so that the output of the direct current power supply voltage of can be interrupted | blocked.

  In this case, for example, the on / off control of the switching element (not shown) included in the forced valve closing circuit 45 shuts off the output of the DC power supply voltage of 12 V to the solenoids of the gas main valve 23 and each gas solenoid valve 24. It is done by

  The solenoid valve drive circuit 44 is configured so that the solenoids of the gas source valve 23 and the respective gas solenoid valves 24 can be energized when the DC power supply voltage of 12 V is output from the forced valve closing circuit 45. The solenoids of the gas solenoid valves 23 and 24 are connected to the secondary side ground 62 on the substrate 11 while being connected to the respective solenoids of the gas solenoid valves 24 via the conductive wires of the harness 12 b.

Furthermore, the solenoid valve drive circuit 44 is connected to the microcomputer 41 on the substrate 11 so that it can receive a control command from the microcomputer 41 and can output a signal indicating the operation state of the solenoid valve drive circuit 44 to the microcomputer 41. The solenoid valve drive circuit 44 energizes the solenoids of the required solenoid valves of the gas source valve 23 and the gas solenoid valve 24 in a predetermined cycle according to a control command given from the microcomputer 41 (pulse drive The solenoid valve is controlled to open by energizing the system, and the solenoid valve is closed by constantly interrupting energization of the solenoid of the solenoid valve.

  In this case, the on / off control of the gas main valve 23 and the gas solenoid valves 24 as described above is performed, for example, by on / off control of a plurality of switching elements (not shown) included in the solenoid valve drive circuit 44.

  Each of the motor drive circuit 43, the solenoid valve drive circuit 44, and the forced valve closing circuit 45 described above is a circuit having a known configuration.

  Each thermistor 25 is connected to the voltage dividing resistor 51 mounted on the substrate 11 corresponding to the thermistor 25 in series between the 5 V potential portion 63 and the secondary ground 62. It is connected to the voltage dividing resistor 51 and the secondary side ground 62 through a conducting wire. Then, the midpoint between the thermistor 25 and the voltage dividing resistor 51 is set so that the voltage between both ends of each thermistor 25 is output to the detection circuit 47 as a detection signal indicating the temperature detected by the thermistor 25. The detection circuit 47 is connected on the substrate 11.

  The water amount sensor 26 and the hot water amount sensor 27 are connected to the conducting wire 12b1 branched from the harness 12b so that a DC power supply voltage of 12 V is supplied from the 12 V electric potential unit 64 via the temperature fuse 22. At the same time, it is connected to the secondary side ground 62 via the conductive wire of the harness 12c.

  The water quantity sensor 26 and the hot water quantity sensor 27 are configured to output a pulse signal according to the water flow rate (the feed water flow rate or the hot water quantity) while the DC power supply voltage of 12 V is supplied. There is. The pulse signal is, for example, a signal in a frequency range of 0 to 400 Hz. Then, the water amount sensor 26 and the hot water amount sensor 27 are detected via the conduction line of the harness 12 c so as to output the pulse signal to the detection circuit 47 as a detection signal of the water flow rate (water supply flow rate or hot water amount). It is connected to the circuit 47.

  The detection circuit 47 is configured to convert a detection signal given to each of the thermistors 25, the water amount sensor 26 and the hot water amount sensor 27 into an input signal for the microcomputer 41, and the input signal to the microcomputer 41. Are connected to the microcomputer 41 on the substrate 11.

  The floor heating remote control 28 and the bathroom heating remote control 29 are connected to the 24 V electric potential portion 65 and the secondary side ground 62 via the conduction line of the harness 12 d so that the DC power supply voltage of 24 V is applied from the substrate 11 side. In addition, the communication circuit 48 is connected to the communication circuit 48 via the conduction line of the harness 12 d so as to communicate with the microcomputer 41 via the communication circuit 48.

  Further, the communication circuit 48 is connected to the microcomputer 41 on the substrate 11 so that the communication data can be transmitted and received to and from the microcomputer 41, and the communication data supplied from the floor heating remote control 28 or the bathroom heating remote control 29 is microcomputer. It is configured to be able to transmit to 41, or to transmit communication data from the microcomputer 41 to the floor heating remote control 28 or the bathroom heating remote control 29 to the corresponding remote control 28 or 29, respectively.

  Communication data between each of the floor heating remote control 28 and the bathroom heating remote control 29 and the microcomputer 41 is data composed of pulse signals in a predetermined frequency band.

  The hot water filling valve 30 and the refilling water valve 31 are constituted by solenoid valves, and one end of each solenoid is supplied with a 12 V DC power supply voltage from the 12 V electric potential part 64 through the temperature fuse 22. The other end of each solenoid is connected to each of the hot water valve drive circuit 49 and the water rehydration valve drive circuit 50 via the conductive wire of the harness 12e while being connected to the conductive wire 12b1 branched from the harness 12b. There is.

  Then, each of the hot water valve drive circuit 49 and the water rehydration valve drive circuit 50 receives the hot water valve 30 and the water rehydration valve 31 with a DC power supply voltage of 12 V applied thereto. It is connected on the substrate 11 to the secondary side ground 62 so that each solenoid of the refill valve 31 can be energized.

Furthermore, each of the hot water valve drive circuit 49 and the water rehydration valve drive circuit 50 is connected to the microcomputer 41 on the substrate 11 so that control commands can be received from the microcomputer 41. The hot water valve drive circuit 49 In response to a control command given from the microcomputer 41, the solenoid of the hot water valve 30 is energized at a predetermined cycle (energized by a pulse drive system) to control the hot water valve 30 to open and control the hot water valve. The hot water filling valve 30 is closed by constantly interrupting the energization of the solenoid of the valve 30.

  Similarly, in response to a control command given from the microcomputer 41, the water rehydration valve drive circuit 50 energizes the solenoid of the water rehydration valve 31 at a predetermined cycle (energizes with a pulse drive system) to make the water rehydration valve 31 The valve opening control is performed, and the energization of the solenoid of the water filling valve 31 is shut off in a steady manner to close the water filling valve 31.

  In this case, the opening and closing control as described above of each of the hot water filling valve 30 and the water filling valve 31 is, for example, on / off of a plurality of switching elements (not shown) included in each of the hot water valve driving circuit 49 and the water filling valve driving circuit 50. It is done by control.

  In the present embodiment, the drive frequency of each of the hot water filling valve 30 and the water filling valve 31 (the frequency of energization of each solenoid) in the case where each of the hot water filling valve 30 and the water filling valve 31 is controlled to open by a pulse drive method. From the drive frequency of the solenoid of each of the hot water valve 30 and the refill valve 31 (frequency of energization of each solenoid) in the case where each of the gas main valve 23 and each gas solenoid valve 24 is controlled to open by pulse drive method Is also a high frequency. In the present embodiment, the drive frequency of each of the hot water filling valve 30 and the refill valve 31 is, for example, 500 Hz, and the drive frequency of each of the gas source valve 23 and each gas solenoid valve 24 is, for example, 250 Hz.

  The ground fault detection circuit 46 corresponds to the ground fault current detector in the present invention. The ground fault detection circuit 46 generates the ground fault in which the current-carrying wire of any of the harnesses 12 electrically conducts to the conductor portion of the housing 2 so that the 5V potential section 63 and the 12V potential section 64 are generated. And when a current (hereinafter referred to as a ground current) that flows through the conductive line in which the ground is generated and the casing 2 is generated from either of the 24 V potential portion 65, according to the magnitude of the ground current. It is configured to be able to generate a detected signal (analog signal).

  The ground fault detection circuit 46 is configured, for example, as shown in FIG. 4 in the present embodiment. The ground fault detection circuit 46 includes a ground fault current detection resistor 72 that generates a voltage according to the ground fault current, a pair of voltage dividing resistors 73 and 74 that divides a voltage generated in the resistor element 72, and a ground fault detection. A zener diode 75 for limiting the upper limit value of the voltage of the detection signal generated by the circuit 46, two noise filter circuits 71 and 76, and a buffer circuit 77 are provided.

  The ground fault current detection resistor 72 has one end connected to the chassis ground potential portion 61 (portion connected to the same potential as the chassis 2) of the substrate 11 through the noise filter circuit 71 that removes high frequency noise components. And the other end is connected to the secondary ground 62 of the substrate 11.

  A series circuit in which the voltage dividing resistors 73 and 74 are connected in series is connected in parallel to the ground current detection resistor 72. The total resistance value of the resistance circuit composed of the voltage dividing resistors 73 and 74 and the resistor 72 for detecting a ground current is the resistance of the voltage dividing resistors 73 and 74 of the resistor 72 for detecting a ground current. The resistance value is set to be sufficiently larger than the resistance value of the ground fault current detection resistor 72 so that the resistance value approximates to the resistance value.

  In this case, the voltage (voltage between both ends of the voltage dividing resistor 74) generated at the middle point between the voltage dividing resistors 73 and 74 is a voltage corresponding to the magnitude of the current flowing through the ground fault current detection resistor 72. The middle point between the voltage dividing resistors 73 and 74 is connected to the input side of the buffer circuit 77 via the noise filter circuit 76 that removes high frequency noise components, and the output side of the buffer circuit 77 is connected to the microcomputer 41. It is done. As a result, the voltage generated at the midpoint between the voltage dividing resistors 73 and 74, that is, the voltage corresponding to the magnitude of the current flowing through the ground fault detecting resistor 72 passes through the noise filter circuit 76 and the buffer circuit 77. It will be input to 41.

  Further, a midpoint between the voltage dividing resistors 73 and 74 is connected to the 5 V potential portion 63 of the substrate 11 via the zener diode 75. Thereby, the upper limit value of the voltage generated at the middle point between the voltage dividing resistors 73 and 74 is limited to 5V.

  In the present embodiment, the ground fault detection circuit 46 is configured as described above.

  Here, any of the 5 V potential portion 63, the 12 V potential portion 64, and the 24 V potential portion 65 due to the occurrence of a ground fault (conduction to the conductor portion of the housing 2) of the current-carrying wire of any harness 12 When a ground current flows from the potential portion of the ground to the housing 2, the ground current flows from the housing 2 through the housing ground potential portion 61 and the noise filter circuit 71. Flow to

  For example, as illustrated in FIG. 5, it is assumed that a ground fault of the current-carrying wire between any one of the gas solenoid valve 24 of the harness 12b and the solenoid valve drive circuit 44 occurs. In this case, as indicated by an arrow Y in a dashed dotted line in FIG. 5, the solenoid of the gas solenoid valve 24, the conducting wire in which a ground fault has occurred, the case 2, the case grounding potential portion 61, and noise from the 12V potential portion 64. The ground fault current flows to the ground fault current detection resistor 72 through the filter circuit 71. The switch element 44 a shown in FIG. 5 is a switch element included in the solenoid valve drive circuit 44.

  As described above, the phenomenon that the ground fault current flows in the ground fault current detection resistor 72 occurs when a ground fault occurs in any of the conductive lines (including the conductive line 12b1) of the harness 12a or the harness 12b shown in FIG. Alternatively, when a ground fault occurs in any of the conducting wires other than the conducting wires connected to the secondary ground 62 among the harness 12c or the harness 12d shown in FIG. 3, or the harness 12e shown in FIG. This is a phenomenon that can occur when a ground fault occurs in any of the current-carrying wires.

  Then, a voltage according to the magnitude of the ground fault current flowing through the ground fault current detection resistor 72 (hereinafter referred to as a ground fault detection voltage) is input to the microcomputer 41. The ground fault detection voltage is a voltage signal substantially proportional to the magnitude of the ground fault current.

  The microcomputer 41 executes a program stored and held in a memory (not shown) to perform operation control of the water heater 1, and based on the ground detection voltage input from the ground detection circuit 46, It has a function of detecting the occurrence of a ground fault, and further identifying the current-carrying wire in which the ground fault has occurred based on the magnitude of the ground fault detection voltage and the change pattern thereof. Therefore, the microcomputer 41 has a function as a current flow line identification unit in the present invention.

  Further, the microcomputer 41 displays information indicating which conducting wire is the conducting wire in which the ground fault has occurred, a display part of a main remote controller (not shown) such as a kitchen remote controller (not shown) connected to the substrate 11 It has a function that can be notified by the display of.

  Here, in the present embodiment, the magnitude of the ground fault current flowing through the ground fault detection resistor 72 at the time of occurrence of the ground fault or the frequency of its change is determined by the type of the electronic component to which the conductive line having the ground fault is connected. Alternatively, it depends on the operating state of the electronic component, or the magnitude of the power supply voltage (5 V or 12 V or 24 V) of the electronic component.

  For example, when a ground fault occurs in any of the conductor lines of the harness 12a related to the stepping motor 21, a ground fault current flowing through the ground fault detection resistor 72 during the operation of the stepping motor 21 to which the conductor line is connected. The voltage V.sub.2 fluctuates at the same frequency as the driving frequency (125 Hz) of the stepping motor 21.

  Also, for example, in the case where a ground fault occurs in the conduction line between any of the gas solenoid valve 24 and the solenoid valve drive circuit 44 in the harness 12 b related to the gas solenoid valve 24, the valve solenoid valve 24 is closed. In this case, the ground fault current flowing through the ground fault current detection resistor 72 is a substantially constant direct current. On the other hand, when the gas solenoid valve 24 is open, the ground fault current flowing through the ground fault current detection resistor 72 fluctuates at the same frequency as the drive frequency (250 Hz) of the gas solenoid valve 24.

  Furthermore, for example, in the case where a ground fault occurs in the conduction line between any of the gas solenoid valve 24 and the solenoid valve drive circuit 44 in the harness 12 b related to the gas solenoid valve 24, the valve solenoid valve 24 is closed. Since the conduction resistance of the solenoid of the gas solenoid valve 24 is different in the valve open state of the gas solenoid valve 24, the magnitude of the ground fault current is also different.

  Also, basically, the magnitude of the ground fault current becomes larger as the power supply voltage (5 V or 12 V or 24 V) of the electronic component corresponding to the conductive line in which the ground fault occurs is higher.

  As described above, the magnitude or frequency of the ground fault current flowing to the ground fault current detection resistor 72 when the ground fault occurs (that is, the magnitude or frequency of the ground fault detection voltage input to the microcomputer 41), Depending on the type of the electronic component to which the current-carrying wire having a ground fault is connected, the operating state of the electronic component, or the magnitude of the power supply voltage (5 V or 12 V or 24 V) of the electronic component Become.

  In the present embodiment, the microcomputer 41 is configured to be able to specify the current-carrying line in which the ground fault has occurred by utilizing the above-mentioned matters.

  In this case, in the present embodiment, in order to be able to specify the conductive wire in which the ground fault has occurred, the electronic component in which the ground fault is generated is the conductive wire connected to which electronic component, or The resistance values of the ground fault current detection resistor 72 and the voltage dividing resistors 73 and 74 of the ground fault detection circuit 46 are set so that the magnitude of the ground fault detection voltage changes as clearly as possible according to the operating state of the electronic component. It is set in advance.

  Thus, the ground fault detection voltage input from the ground fault detection circuit 46 to the microcomputer 41 is, for example, as normal when no ground fault occurs and when a ground fault occurs, as shown in FIGS. 6 and 7. Thus, the voltages of different magnitudes become different depending on which conducting wire is the conducting wire in which the ground fault has occurred. Furthermore, the frequency of the ground fault detection voltage matches or substantially matches the drive frequency of the electronic component to which the current-carrying wire in which the ground fault has occurred is connected.

  FIG. 6 shows the magnitude and frequency of the ground fault detection voltage in the standby state in which the water heater 1 is not operated (hot water supply operation, bath operation, and heating operation). As illustrated, in the normal state in which no ground fault occurs, the ground fault detection voltage falls within the range of 0.2 V or less, as indicated by a region R1.

  Then, in the standby state, for example, the conducting wire of any of the thermistors 25 (specifically, the conducting wire between the thermistor 25 and the voltage dividing resistor 51) or the conducting wire of the gas source valve 23 (in detail, the gas The conduction line between the solenoid of the main valve 23 and the solenoid valve drive circuit 44) or the conduction line of any gas solenoid valve 24 (specifically, between the solenoid of the gas solenoid valve 24 and the solenoid valve drive circuit 44 When a ground fault occurs in the current-carrying wire), a ground fault detection voltage having a magnitude within the range of 0.2 to 2 V is generated as indicated by the region R2. This ground fault detection voltage is a voltage of a substantially constant value (about 0 Hz).

  In addition, in the standby state, for example, a conducting wire to which a DC power supply voltage of 12 V is applied (specifically, each conducting wire connected to both ends of the thermal fuse 22 or the conducting wire 12b1 or a gas source valve 23 or each gas In the case where a ground fault of a conductive wire having approximately the same potential as that of the 12 V potential portion 64 occurs, such as a conductive wire between the solenoid of the solenoid valve 24 and the forced valve closing circuit 45, as shown by region R3, A ground detection voltage of a magnitude within the range of 4.5 V is generated. This ground fault detection voltage is a voltage of a substantially constant value (about 0 Hz).

  In addition, in the standby state, a ground fault occurs in a conducting line to which a DC power supply voltage of, for example, 24 V is applied (specifically, a conducting line between the floor heating remote control 28 or the bathroom heating remote control 29 and the 24 V potential unit 65) In this case, as indicated by region R4, a ground detection voltage having a magnitude within the range of 4.5 to 5 V is generated. This ground fault detection voltage is a voltage of a substantially constant value (about 0 Hz).

  In addition, in the standby state, a ground fault of communication wire for communication of floor heating remote control 28 or bathroom heating remote control 29 (specifically, conductive line between floor heating remote control 28 or bathroom heating remote control 29 and communication circuit 48) If there is a ground fault detection voltage that fluctuates in a certain frequency band (for example, a frequency band of 125 Hz or more) with a size within the range of 4.5 to 5 V as shown in the region R5 .

  Further, FIG. 7 shows the magnitude and frequency of the ground fault detection voltage in a state where any electronic component such as the stepping motor 21 is operating by the operation (hot water supply operation, bath operation or heating operation) of the water heater 1 And represents. As illustrated, in the normal state in which no ground fault occurs, the ground fault detection voltage falls within the range of 0.2 V or less, as indicated by the region R11, as in the case of the standby state.

  On the other hand, for example, when the water amount sensor 26 or the hot water amount sensor 27 is activated, the conducting line of the water amount sensor 26 or the hot water amount sensor 27 (specifically, the water amount sensor 26 or the hot water amount sensor 27 and the detection circuit 47 In the case where a ground fault occurs in the electric conduction line between), a ground fault detection voltage having a magnitude within the range of 1 to 3 V is generated as indicated by a region R12. This ground fault detection voltage is a voltage that causes fluctuation in a certain frequency band (for example, a frequency band of about 125 to 400 Hz).

  Also, for example, when a ground fault occurs in the current-carrying wire of the stepping motor 21 (more specifically, the current-carrying wire between the stepping motor 21 and the motor drive circuit 43) when any of the stepping motors 21 operates. As indicated by region R13, a ground fault detection voltage of a magnitude within the range of 3 to 4.5 V is generated. The ground fault detection voltage is a voltage which causes a fluctuation at a frequency of 125 Hz which is a driving frequency of the stepping motor 21.

  Also, for example, at the time of opening control of the gas main valve 23 or any one of the gas solenoid valves 24, the conduction line of the gas main valve 23 or the gas solenoid valve 24 (specifically, of the gas main valve 23 or the gas solenoid valve 24 When a ground fault occurs in the conductive line between the solenoid and the forced valve closing circuit 45, a ground fault detection voltage having a magnitude within the range of 3 to 4.5 V is generated as indicated by the region R14. The ground fault detection voltage is a voltage which causes a fluctuation at a frequency of 250 Hz which is a drive frequency at the time of opening control of each of the gas main valve 23 and each gas solenoid valve 24.

  Also, for example, at the time of opening control of the hot water filling valve 30 or the refilling valve 31, the conduction line of the hot water filling valve 30 or the filling valve 31 (specifically, the solenoid of the hot filling valve 30 or the filling valve 31 and the hot water filling valve drive When a ground fault occurs in the conductive line between the circuit 49 or the water rehydration valve drive circuit 50, a ground fault detection voltage having a magnitude within the range of 3 to 4 V is generated as indicated by the region R15. This ground fault detection voltage is a voltage which causes a fluctuation at a frequency of 500 Hz which is a drive frequency at the time of the valve opening control of each of the hot water valve 30 and the water refill valve 31.

  Next, processing of the microcomputer 41 regarding detection of a ground fault will be specifically described with reference to the flowcharts of FIGS.

  The microcomputer 41 executes the processing shown in the flowcharts of FIGS. 8 to 11 in a state where the power is turned on (the power of the commercial power is supplied to the substrate 11).

  In STEP 1, the microcomputer 41 acquires the ground fault detection voltage Vx input from the ground fault detection circuit 46.

  Then, the microcomputer 41 executes a process of determining whether the acquired ground fault detection voltage Vx is larger than 0.2 V in STEP2. In the present embodiment, in the processing of the microcomputer 41, the ground fault detection voltage Vx to be compared with a certain threshold such as 0.2 V is a voltage value when the Vx is a constant voltage. In the case of a periodically fluctuating voltage, it is a peak value.

  The situation where the determination result of STEP 2 is negative is the normal state in which no ground fault has occurred, as shown by the area R1 of FIG. 6 or the area R11 of FIG. In this case, the microcomputer 41 repeats the processing from STEP 1 on the assumption that the normal state is established in STEP 3.

  The situation in which the determination result in STEP 2 is positive is a situation in which a ground fault in which any of the current-carrying wires is conducted to the housing 2 has occurred. In this case, the microcomputer 41 next determines in STEP 4 whether the state of the water heater 1 is in the standby state. Then, when the state of the water heater 1 is in the standby state (when the determination result in STEP 4 is affirmative), the microcomputer 41 determines which of the conducting lines in which the ground fault has occurred (hereinafter referred to as the ground conducting line) The process from STEP 5 is executed to identify whether it is a conductive line, and when it is not in the standby state (the hot water supply operation, or the bath operation, or the heating operation is performed, the determination result of STEP 4 becomes negative) In case (1), the processing from STEP 24 described later is executed to specify which current conductor is the ground conductor.

  In STEP5 when the water heater 1 is in the standby state, the microcomputer 41 puts the water heater 1 in the operation prohibited state in STEP6, and acquires the ground fault detection voltage Vx again in STEP6.

  Then, the microcomputer 41 sets the range where the ground fault detection voltage Vx is Vx> 4.5V, the range where 3V <Vx ≦ 4.5V, the range where 0.2V <Vx ≦ 3V, Vx ≦ 0 in STEP 7 2. Determine which range of the range of 2 V belongs.

  The range of Vx> 4.5 V is a range to which the regions R4 and R5 shown in FIG. 6 belong. For this reason, it can be considered that a ground fault has occurred in the floor heating remote control 28 or the conduction line of the bathroom heating remote control 29 (the conduction line to which the DC power supply voltage of 24 V is applied, or the communication line).

  Therefore, if Vx> 4.5 V in STEP7, the microcomputer 41 determines whether or not the frequency of the ground fault detection voltage Vx is 0 Hz (or almost 0 Hz) in STEP 8 (in other words, Vx is approximately It is judged whether or not it is a constant voltage signal of a fixed value.

  If the determination result is affirmative, the microcomputer 41 determines in STEP 9 that the ground-fault conduction line is the conduction line to which the 24 V DC power supply voltage of the floor heating remote control 28 or the bathroom heating remote control 29 is applied (floor heating Identifying the remote control 28 or the bathroom heating remote control 29 as the conduction line between the 24V potential portion 65 of the substrate 11) and indicating that fact via the display section of the main remote control such as a kitchen remote control Output.

  If the determination result in STEP 8 is negative, the microcomputer 41 in STEP 10 communicates with the floor heating remote control 28 or the bathroom heating remote control 29 (the floor heating remote control 28 or the bathroom). It identifies as a conduction line between the heating remote controller 29 and the substrate 11 communication circuit 48, and outputs error information indicating that through the display section or the like of the main remote controller such as a kitchen remote controller.

  In the standby state of the water heater 1, the range in which the ground fault detection voltage Vx is 3V <Vx ≦ 4.5V is a range to which the region R3 shown in FIG. 6 belongs. For this reason, it can be considered that a ground fault has occurred in the current-carrying wire to which a DC power supply voltage of 12 V is applied.

  Therefore, if it is 3V <Vx ≦ 4.5V in STEP7, the microcomputer 41 determines that the ground-fault conduction line is a conduction line to which a DC power supply voltage of 12V is applied in STEP11. An error indicating that it is identified as the connected conducting wire or the conducting wire 12b1 or the conducting wire between the solenoid of the gas main valve 23 or the solenoid of each gas solenoid valve 24 and the forced closing circuit 45) Information is output via a display unit or the like of a main remote controller such as a kitchen remote controller.

  In the standby state of the water heater 1, the range in which the ground fault detection voltage Vx is 0.2 V <Vx ≦ 3 V is the range to which the region R2 shown in FIG. 6 belongs. For this reason, it can be considered that a ground fault of any one of the conduction lines of the thermistor 25 or the conduction line of the gas main valve 23 or the conduction line of any of the gas solenoid valves 24 has occurred.

  In this case, the microcomputer 41 executes the processing from STEP12 of FIG. 9 in order to specify the ground-fault conduction line in more detail.

  In STEP 12, the microcomputer 41 controls the opening of one of the gas main valve 23 and the gas solenoid valve 24, for example, the gas main valve 23 via the solenoid valve drive circuit 44. The other solenoid valves (here, all the gas solenoid valves 24 other than the gas main valve 23) are maintained in the closed state.

  Then, in a state in which the gas main valve 23 is open-controlled in this manner, the microcomputer 41 acquires the ground fault detection voltage Vx input from the ground fault detection circuit 46 in STEP 12 and the ground fault detection voltage Vx is It is determined in STEP 14 whether the voltage is in the range of 3V <Vx ≦ 4.5V.

  Since the ground fault detection voltage Vx in a state in which only the main gas valve 23 is controlled to be opened belongs to the region R14 shown in FIG. It can be considered that a ground fault of the conducting wire (a conducting wire between the solenoid of the gas main valve 23 and the solenoid valve drive circuit 44) has occurred.

  Therefore, if the determination result in STEP 14 is affirmative, the microcomputer 41 closes the gas source valve 23 via the solenoid valve drive circuit 44 in STEP 15, and the ground-fault conduction line is the gas source valve 23. And the error information indicating that effect is output through the display unit or the like of the main remote controller such as the kitchen remote controller.

  Further, if the determination result in STEP 14 is negative, the microcomputer 41 next closes the gas main valve 23 via the solenoid valve drive circuit 44 and distinguishes the gas solenoid valve 24 in STEP 16. The value of the identification number i is “1”.

  Then, the microcomputer 41 determines whether or not the current value of the identification number i is equal to or less than the total number of gas solenoid valves 24 in STEP17.

  When i = 1, the determination result of STEP17 becomes affirmative. Then, if the determination result of STEP 17 is affirmative, the microcomputer 41 performs the valve opening control of the i th gas solenoid valve 24 via the solenoid valve drive circuit 44 in STEP 18. The other solenoid valves (here, all the gas solenoid valves 24 and the gas main valve 23 other than the i-th gas solenoid valve 24) are maintained in the closed state.

  Thus, in a state where the i-th gas solenoid valve 24 is controlled to open, the microcomputer 41 acquires the ground fault detection voltage Vx input from the ground fault detection circuit 46 in STEP 19 and the ground fault detection voltage Vx is At STEP 20, it is determined whether the voltage is in the range of 3V <Vx ≦ 4.5V.

  Since the ground fault detection voltage Vx in the state where only the ith gas solenoid valve 24 is controlled to be opened belongs to the region R14 shown in FIG. It can be considered that a ground fault of the conduction line of the gas solenoid valve 24 (the conduction line between the solenoid of the gas solenoid valve 24 and the solenoid valve drive circuit 44) has occurred.

  Therefore, if the determination result in STEP 20 is affirmative, the microcomputer 41 closes the i-th gas solenoid valve 24 via the solenoid valve drive circuit 44 in STEP 22 and the ground-fault conduction line is i It identifies as the conduction line of the gas solenoid valve 24 of No., and outputs error information indicating that through the display part or the like of the main remote controller such as a kitchen remote controller.

  When the determination result in STEP 20 is negative, the microcomputer 41 closes the i-th gas solenoid valve 24 via the solenoid valve drive circuit 44 in STEP 21 and sets the value of the identification number i After increasing the value by 1 ", the process from STEP 17 is executed again.

  The situation where the determination result of STEP 17 is negative is a situation where it can be considered that no ground fault has occurred in the main valve of gas main valve 23 and the current-carrying wire of the gas solenoid valve 24. Therefore, when the determination result in STEP 17 is negative, it can be considered that a ground fault has occurred in any of the current-carrying lines of the thermistor 25 (the current-carrying line between the thermistor 25 and the voltage dividing resistor 51).

  Therefore, if the determination result in STEP 17 is negative, the microcomputer 41 determines in STEP 23 that the ground-fault current-carrying wire is a current-carrying wire of any of the thermistors 25, and indicates error information indicating that effect. It outputs through the display part etc. of main remote controls, such as a kitchen remote control.

  Further, in the above STEP 7 in the standby state of the water heater 1, the range in which the ground fault detection voltage Vx is Vx ≦ 0.2 V is the range to which the region R1 shown in FIG. 6 belongs, ie, the ground fault is generated. There is no range of Vx in normal condition. Therefore, when Vx ≦ 0.2 V in STEP7, the microcomputer 41 restarts the process from STEP1 without outputting the error information.

  Here, the microcomputer 41 continues the process from STEP 5 after the process of any one of STEPs 9, 10, 11, 22, and 23 is executed. In this case, if the cause of the occurrence of the ground fault is eliminated by changing or replacing the wiring path of the current-carrying wire in which the ground fault has occurred, Vx ≦ 0.2 V in STEP7. As a result, the process from STEP 1 is resumed.

  When a ground fault occurs while the water heater 1 is in the standby state, the process of specifying the ground fault current-passing line is performed as described above. In this case, the ground-fault conduction line can be roughly identified by classifying and judging the ground-fault detection voltage Vx into four types of ranges in STEP7.

  Furthermore, when Vx> 4.5V in STEP7, the DC power supply voltage of 24V of the floor heating remote control 28 or the bathroom heating remote control 29 is applied by judging the frequency of the ground fault detection voltage Vx in STEP8. A current-carrying wire can be identified by distinguishing it from the current-carrying wire for communication.

  When 0.2 V <Vx ≦ 3 V in STEP7, the gas main valve 23 and the gas solenoid valve 24 are sequentially opened and controlled, and the ground fault detection voltage Vx at the respective valve opening control (operation) time Based on the above, the process of determining whether or not a ground fault occurs in each of the gas main valve 23 and the gas solenoid valve 24 is sequentially executed. Thereby, in the case of 0.2 V <Vx ≦ 3 V in STEP 7, it is properly specified which of the gas main valve 23, the gas solenoid valve 24, and the thermistor 25 is a conductive wire of the ground connection conductive wire. be able to.

  Next, if the determination result of the STEP 4 is negative, that is, Vx> 0.2 V in STEP 2 and the occurrence of a ground fault is detected, the state of the water heater 1 is the operation state (hot water supply operation Or, in the case where the bath operation or the heating operation is performed, the microcomputer 41 executes the processing from STEP 24 of FIG.

  In STEP 24, the microcomputer 41 acquires the ground fault detection voltage Vx input from the ground fault detection circuit 46. Then, the microcomputer 41 determines in step 25 which range the ground fault detection voltage Vx is in the range of Vx> 3 V, the range of 0.2 V <Vx ≦ 3 V, and the range of Vx ≦ 0.2 V. to decide.

  The range in which Vx> 3 V is a range to which the regions R13, R14, and R15 shown in FIG. 7 belong. And in this embodiment, when the earth fault of the energization line of either the gas main valve 23 or the gas solenoid valve 24 has occurred, the specification of the said ground fault energization line is the water heater 1 as mentioned above. In standby mode.

  For this reason, if Vx> 3 V in STEP 25, either the current-carrying line of the stepping motor 21 (the current-carrying line between the stepping motor 21 and the motor drive circuit 43) or the hot water valve 30 or the refill valve A ground fault is generated on the 31 conducting wires (a conducting wire between the solenoid of the hot water valve 30 and the hot spring valve drive circuit 49, or a conductive line between the solenoid of the water refill valve 31 and the water refill valve drive circuit 50) It can be regarded as having done.

  In this case, the microcomputer 41 executes the processing from STEP 26 in order to specify the ground-fault conduction line in more detail.

  At STEP 26, the microcomputer 41 determines whether the frequency of the ground fault detection voltage Vx acquired at STEP 24 matches or almost matches the drive frequency of 125 Hz of the stepping motor 21.

  If the determination result in STEP 26 is affirmative, it can be considered that a ground fault has occurred in any of the current-carrying wires of the stepping motor 21. Then, in this case, the microcomputer 41 first forcibly stops the operation of the water heater 1 in STEP 27 and then specifies which of the stepping motors 21 the current-carrying wire in which the ground fault has occurred is the current-carrying wire. The process is executed from STEP28.

  At STEP 28, the microcomputer 41 sets the value of the identification number j for distinguishing the stepping motor 21 to "1".

  Next, in STEP 29, the microcomputer 41 causes the stepping motor 21 to be supplied with power via the motor drive circuit 43 corresponding to the stepping motor 21 so as to operate the jth stepping motor 21 in a predetermined mode.

  Then, in a state where the jth stepping motor 21 is operated in this manner, the microcomputer 41 acquires the ground fault detection voltage Vx input from the ground fault detection circuit 46 in STEP 30, and the ground fault detection voltage Vx is It is determined in STEP 31 whether the voltage is in the range of 3V <Vx ≦ 4.5V.

  Since the ground fault detection voltage Vx in a state in which only the jth stepping motor 21 is operated belongs to the region R13 shown in FIG. It can be considered that a ground fault has occurred in the conducting wire of the motor 21 (the conducting wire between the stepping motor 21 and the corresponding motor drive circuit 43).

  Therefore, if the determination result in STEP 31 is affirmative, the microcomputer 41 stops the operation of the jth stepping motor 21 in STEP 33, and the ground-fault conduction line is the conduction line of the j-th stepping motor 21. It identifies as it, and outputs the error information which shows that through the display part etc. of main remote controllers, such as a kitchen remote control.

  If the determination result in STEP 31 is negative, the microcomputer 41 stops the operation of the jth stepping motor 21 in STEP 32, and increases the value of the identification number j by “1”. , The process from STEP 29 is executed again.

  If the determination result of STEP 26 is affirmative, as described above, it is specified which of the current-carrying lines of the stepping motor 21 has caused the ground fault.

  On the other hand, if the determination result in STEP 26 is negative, it can be considered that the current-carrying wire in which the ground fault has occurred is the current-carrying wire of either the hot water valve 30 or the refill valve 31. Then, in this case, the microcomputer 41 further executes a process from STEP 34 in order to specify which of the current-carrying lines of the hot water filling valve 30 and the water filling valve 31 has a ground fault.

  In STEP 34, the microcomputer 41 forcibly stops the operation of the water heater 1, and opens one of the hot water valve 30 and the refill valve 31, for example, the hot water valve 30, via the hot water valve drive circuit 49. Control the valve.

  Then, in a state where the hot water filling valve 30 is open-controlled in this way, the microcomputer 41 acquires the ground fault detection voltage Vx input from the ground fault detection circuit 46 in STEP 35, and the ground fault detection voltage Vx is At STEP 36, it is determined whether Vx> 0.2V.

  The situation where the judgment result is affirmative is that the ground fault detection voltage Vx in the state where the hot water filling valve 30 is controlled to be opened belongs to the region R15 shown in FIG. It can be considered that a ground fault has occurred in the conducting wire (a conducting wire between the solenoid of the hot spring valve 30 and the hot spring valve drive circuit 49).

  Therefore, if the determination result in STEP 36 is affirmative, the microcomputer 41 closes the hot water valve 30 in STEP 37, and specifies that the ground conduction wire is the conductive wire of the hot water filling valve 30. The error information indicating that is output through a display unit or the like of a main remote controller such as a kitchen remote controller.

  Further, the situation where the judgment result in STEP 36 is negative is that the ground fault detection voltage Vx in the state where the hot water valve 30 is controlled to be opened is the value at the normal time when the ground fault is not generated. It can be considered that a ground fault of the 31 conducting wires (a conducting wire between the solenoid of the water refill valve 31 and the water refill valve drive circuit 50) has occurred.

  Therefore, if the determination result in STEP 36 is negative, the microcomputer 41 closes the hot water fill valve 30 in STEP 38 and specifies that the ground-fault conduction line is the conduction line of the water rehydration valve 31, The error information indicating that is output through the display unit or the like of the main remote controller such as the kitchen remote controller.

  As described above, when Vx> 3 V in STEP 25, it is specified by the processing in STEPs 26 to 38 which of the energization lines of the stepping motor 21, the hot water valve 30 and the water rehydration valve 31 has generated a ground fault. Ru.

  In STEP 26, for example, it is determined whether or not the frequency of Vx matches or substantially matches 500 Hz which is the drive frequency of the opening control of hot water valve 30 and refill valve 31, and the determination result is negative. Alternatively, the processing from STEP 27 may be executed, and if affirmative, the processing from STEP 34 may be executed.

  Next, in STEP 25, the range in which the ground fault detection voltage Vx is 0.2 V <Vx ≦ 3 V is a range to which the region R12 shown in FIG. 7 belongs. For this reason, when it becomes 0.2V <Vx ≦ 3V in STEP25, the conductive wire of the water quantity sensor 26 or the hot water quantity sensor 27 (between the water quantity sensor 26 or the hot water quantity sensor 27 and the detection circuit 47 It can be considered that a ground fault has occurred in the conducting wire).

  In this case, the microcomputer 41 executes the processing from STEP 39 of FIG. 11 in order to specify the ground-fault conduction line in more detail. In STEP 39, the microcomputer 41 forcibly stops the operation of the water heater 1, and then starts hot water pouring to the bathtub again. Hot water to the bath is started by controlling the hot water valve 30 to open.

  As described above, the microcomputer 41 is input from the ground fault detection circuit 46 in STEP 40 in a state where the hot water is poured into the bathtub (in other words, the hot water amount sensor 27 can detect the hot water amount). Is obtained, and it is determined in STEP 41 whether or not the ground fault detection voltage Vx is 0.2V <Vx ≦ 3V.

  Since the ground fault detection voltage Vx in the state where the hot water amount sensor 27 can detect the hot water flow rate belongs to the region R15 shown in FIG. It can be considered that a ground fault of the conducting wire of the amount sensor 27 (the conducting wire between the hot water amount sensor 27 and the detection circuit 47) has occurred.

  Therefore, if the determination result in STEP 41 is affirmative, the microcomputer 41 stops the hot water pouring to the bathtub (closes the hot water filling valve 30) in STEP 42, and the ground fault conducting wire It identifies as the conduction line of the amount sensor 27, and outputs error information indicating that through the display section or the like of the main remote controller such as a kitchen remote controller.

  Further, if the determination result in STEP 41 is negative, the microcomputer 41 stops the hot water pouring to the bathtub (closes the hot water filling valve 30) in STEP 43, and also the ground fault conducting wire is a water quantity sensor It identifies as the 26 conducting wires, and outputs error information indicating that through the display section or the like of the main remote controller such as a kitchen remote controller.

  Further, at STEP 25 when the water heater 1 is in operation, the range in which the ground fault detection voltage Vx is Vx ≦ 0.2 V is the range to which the region R11 shown in FIG. There is no range of Vx in normal condition. Therefore, if Vx ≦ 0.2 V in STEP 25, the microcomputer 41 restarts the processing from STEP 1 without outputting the error information.

  Here, the microcomputer 41 continues the process from STEP 24 after executing the process of any one of STEPs 33, 38, 42, and 43. In this case, if the cause of the occurrence of the ground fault is eliminated by changing or replacing the wiring path of the conducting wire in which the ground fault has occurred, Vx ≦ 0.2 V is obtained in STEP 25. As a result, the process from STEP 1 is resumed.

  When a ground fault occurs in the operating state of the water heater 1, the processing for specifying the ground fault current-carrying wire is performed as described above. In this case, the ground-fault conduction line can be roughly identified by classifying and judging the ground-fault detection voltage Vx into three types of ranges in STEP 25.

  Then, if Vx> 3 V in STEP25, the frequency of the ground fault detection voltage Vx is determined in STEP26 to separate the conduction line of the stepping motor 21 and the conduction line of the hot water valve 30 and the water rehydration valve 31. Separately, it is possible to identify the ground-fault current-carrying wire.

  Furthermore, if the determination result in STEP 26 is affirmative, the plurality of stepping motors 21 are operated in order, and for each energizing line of the stepping motor 21 based on the ground fault detection voltage Vx at each operation. The process of determining whether or not the current-carrying wire has a ground fault is sequentially performed. Thus, it can be properly specified which of the stepping motors 21 is the current-carrying wire of the ground-contact current-carrying wire.

  In addition, when the judgment result of STEP 26 is negative, the magnitude of the ground fault detection voltage Vx is set to STEP 36 in a state where the open valve of the hot water fill valve 30, for example, the hot water fill valve 30 is controlled. It can be appropriately specified whether the ground-fault current-carrying wire is any current-carrying wire of the hot water valve 30 or the water refueling valve 31 by judging.

  In addition, when 0.2 V <Vx ≦ 3 V in STEP25, the level of the ground fault detection voltage Vx is determined in STEP41 with the hot water level of the bath being operated and the hot water amount sensor 27 being operated. Thus, it can be properly specified which of the water quantity sensor 26 and the hot water quantity sensor 27 is the ground conducting wire.

  As described above, according to the present embodiment, when a ground fault occurs, it is possible to properly identify the ground conductive line. Then, by notifying the identified ground-fault current-carrying wire, the operator who performs the work for eliminating the ground-fault can recognize which current-carrying wire has caused the ground-fault, so that the ground-foil elimination work (ground-fed occurred The replacement of the conducting wire, the correction of the arrangement path of the conducting wire, etc. can be easily performed in a short time.

  The present invention is not limited to the embodiments described above. Several other embodiments are described below. For example, when the frequency of the ground fault detection voltage Vx acquired in STEP 6 belongs to the communication frequency band of the floor heating remote control 28 and the bathroom heating remote control 29, the ground fault conducting line is selected regardless of the size of Vx. It may be specified that it is a conductive wire for communication of the floor heating remote control 28 or the bathroom heating remote control 29.

  Also, for example, when the ground fault detection voltage Vx acquired in STEP 13 is a substantially constant voltage (when the frequency is approximately 0 Hz), either of the ground fault current-carrying wires is used regardless of the magnitude of Vx. It may be specified that it is a conductive wire of the thermistor 25.

  Further, for example, when the ground fault detection voltage Vx acquired in STEP 24 matches or almost matches the drive frequency 125 Hz of the stepping motor 21, the ground fault current-carrying wire is selected regardless of the size of Vx. It may be specified that it is a current-carrying line of the stepping motor 21.

  Further, at STEP 34, instead of controlling the hot water filling valve 30 to open, the water rehydration valve 31 is controlled to open, and the ground fault detection voltage Vx acquired in this state is a ground fault when Vx> 0.2V. The conductive wire may be specified as the conductive wire of the water rehydration valve 31.

  Further, in the above embodiment, the frequency of Vx is used as an index representing a change pattern of the ground detection voltage Vx. However, the ground-fault conduction line may be specified based on a change pattern or the like of the ground-fault detection voltage Vx when the operation state of a certain electronic component is changed from a predetermined state to another state.

  In addition, the ground fault detection circuit 46 may be a circuit having a configuration different from that of the above embodiment as long as it can detect a ground fault current.

  Furthermore, in the said embodiment, although the bath water heater 1 with a hot-water heating function was illustrated as an apparatus in this invention, the apparatus to which this invention is applied is a hot-water heater which is not equipped with a hot-water heating function, for example. Good. Furthermore, the present invention is applicable not only to a water heater but also to various devices such as an air conditioning system.

  DESCRIPTION OF SYMBOLS 1 ... bath water heater (apparatus) with a hot water heating function, 2 ... housing | casing, 12 (12a-12e) ... harness (electric current line), 41 ... microcomputer (electric current line identification part), 46 ... ground fault detection circuit (ground Current detector).

Claims (6)

This is a phenomenon in which a conductor portion of the case and a current-carrying wire for conduction of any one of the electronic components are conducted in an apparatus provided with a housing in which a current-carrying conduction wire for energizing a plurality of electronic components is provided. It is a ground fault detection device having a function of specifying which electronic component is a current carrying wire for current conduction of the electronic component when the ground fault is generated,
When the ground fault occurs, a ground fault current which is a current flowing through the conductive line and the casing in which the ground fault has occurred is detected, and an output corresponding to the magnitude of the ground fault current is generated. Ground current detector,
The current-carrying wire in which the ground fault has occurred is identified based on at least one of the magnitude of the ground fault current indicated by the output of the ground fault current detector and the change pattern of the magnitude of the ground fault current. A ground fault detection device comprising: a wire identification unit. In the ground fault detection device according to claim 1,
In the conductive wire specifying unit, the magnitude of the ground fault current indicated by the output of the ground fault current detector when the ground fault occurs belongs to any one of a plurality of types of preset ranges. Determination of at least one of the judgment result of the current and the judgment result as to which kind of change pattern among the plurality of kinds of change patterns set in advance is the change pattern of the magnitude of the ground fault current A ground fault detection device characterized in that it is configured to specify the current-carrying wire in which the ground fault has occurred based on the result. In the ground fault detection device according to claim 1 or 2,
The conductive line identification unit identifies the conductive line in which the ground fault has occurred, using the fluctuation frequency of the magnitude of the ground fault current indicated by the output of the ground fault current detector as an index representing the change pattern. A ground fault detection device characterized in that it is configured as follows. In the ground fault detection device according to any one of claims 1 to 3,
Among at least some of the plurality of conductive lines of the plurality of electronic components, it is specified which of the plurality of conductive lines has caused a ground fault. In this case, for each of the plurality of conductive wires, it is determined whether or not a ground fault has occurred in the conductive wires in a predetermined order for the plurality of conductive wires. A ground fault detection device configured to execute. In the ground fault detection device according to any one of claims 1 to 4,
The conductive wire identification unit corresponds to the predetermined conductive wire in order to determine whether or not a ground fault has occurred in the predetermined conductive wire among the conductive wires for energizing the plurality of electronic components. The electronic component is operated, and the magnitude of the ground fault current indicated by the output of the ground fault current detector in the operating state is at least one of the magnitude of the ground fault current and the change pattern of the magnitude of the ground fault current. A ground fault detection device configured to determine whether or not a ground fault of a predetermined current-carrying wire has occurred. In the ground fault detection device according to any one of claims 1 to 5,
The conductive wire identification unit identifies the conductive wire in which the ground fault has occurred in each of different modes in a standby state in which the device is not in operation and in an operation state in which the device is in operation. A ground fault detection device characterized in that it is configured as follows.